1. The problem statement, all variables and given/known data There is a disk with mass 50 grams put on a slippy surface (no friction!). Its radius is 5 cm. Mass of the weight is 20 grams. At the beginning there is no motion. How far does the center of mass of the disk move in 10 seconds? (answer: 91 m) How many turns does the disk in 10 seconds? 2. Relevant equations F=ma F*r = J*alpha 3. The attempt at a solution The only force on the disk is the force of the rope if there is no friction. --> I did not solved the second question as the first answer is wrong. Please help me, correct me.